Front end loader type vehicle

ABSTRACT

THIS SPECIFICATION DISCLOSES AN IMPROVEMENT IN A FRONT END LOADER TYPE VEHICLE CHARACTERIZED BY A LINKAGE ARRANGEMENT BETWEEN A TILTING MEANS AND A BUCKET THAT INHERENTLY EFFECTS A NORMAL GROUND LEVEL LOADING POSITION OF THE BUCKET WITH THE DESIRED TILT ATTITUDE WHEN THE BUCKET IS MERELY LOWERED FROM ITS FULL DUMP TILT AT ITS TOP POSITION. NO SKILLFUL OR TIME-CONSUMING COOPERATIVE MANIPULATION BETWEEN THE TILTING MEANS AND AN ELEVATING MEANS IS REQUIRED. TO ACCOMPLISH THE ABOVE RESULT WITHOUT SIGNIFICANT ENGINEERING SACRIFICES, THERE IS EMPLOYED, INTER ALIA, A BELL CRANK THAT HAS A RATIO OF LENGTHS OF A SECOND LEVER ARM, CONNECTED WITH THE BUCKET, TO A FIRST LEVER ARM, CONNECTED WITH THE TILTING MEANS, OF 1.4-2.0. THE OTHER COMNENTS ARE SELECTED TO EFFECT NEARLY OPTIMUM ANGLES OF TIP BACK, CARRY AND DUMP, AND TO ENABLE ELEVATING THE LOADED, TILTED BACK BUCKET TO THE TOP WITHOUT SPILLING THE LOAD BY MERELY ELEVATING THE BUCKET, WITHOUT ADJUSTING THE TILTING MEANS.

Sept. 20, 19711 1.. A. MOLBY 3,606.

Y mom nun LOADER TYPE VEHICLE l'ilnd Jugs 23', 1969 2 Sheets-Shut 1Sept. 20, 197'] 1.. A. MOLBY 3,606,061

FRONT END LOADER TYPE VEHICLE Filed Jane 23, 1969 2 Sheets-Sheet 2INVENTOR ATTORNEYS United States Patent 3,606,061 FRONT END LOADER TYPEVEHICLE Lloyd A. Molby, Longview, Tex., assignor to R. G. LeTourneauInc., Longview, Tex. Filed June 23, 1969, Ser. No. 835,464 Int. Cl. E02f3/80 US. Cl. 214-776 4 Claims ABSTRACT OF THE DISCLOSURE Thisspecification discloses an improvement in a front end loader typevehicle characterized by a linkage arrangement between a tilting meansand a bucket that inherently effects a normal ground level loadingposition of the bucket with the desired tilt attitude when the bucket ismerely lowered from its full dump tilt at its top position. No skillfulor time-consuming cooperative manipulation between the tilting means andan elevating means is required. To accomplish the above result withoutsignificant engineering sacrifices, there is employed, inter alia, abell crank that has a ratio of lengths of a second lever arm, connectedwith the bucket, to a first lever arm, connected with the tilting means,of 1.4-2.0. The other components are selected to effect nearly optimumangles of tip back, carry and dump; and to enable elevating the loaded,tilted back bucket to the top without spilling the load by merelyelevating the bucket, without adjusting the tilting means.

BACKGROUND OF THE INVENTION This invention relates to so-called frontend loader type machines and particularly to self-propelled wheeled typefront end loaders having a bucket attached for powered pivotal movementto the outer end portion of a main beam, or boom, which in turn isattached at its inner end portion to the front end portion of thevehicle main frame and powered for pivoting elevational movement about atransverse horizontal axis.

In front end loaders of this type, material is normally scooped from asurface by a cutting edge carried on the forward portion of the scoopside of the bucket. Conventionally, linkage means supports the bucket indifferent pivotal positions relative to the end of the main beam. Thus,with a desired tilt attitude; ordinarily, with the scoop side of thebucket substantially horizontal; the vehicle is moved forward to loadthe bucket. Thereafter, the bucket is tipped backward to retain the loadin the bucket and the main beam elevated to a top position. The load isthen carried in this top position until over a dump receptacle, forexample an earth mover hauler. The bucket is rapidly moved into the fulldump position to dump the load into the receptacle. The operator thenreturns to pick up a second load and must, in the usual case,simultaneously lower the main beam and reposition the bucket to attainthe desired tilt attitude at the ground level by operating both anelevating means connected between the main beam and the frame and atilting means for tilting the bucket. It is readily apparent that thecoordinated action of the elevating means and tilting means requisite toachieve the desired results is time consuming even for a skilledoperator.

An important objective of the present invention is to make possible thelowering of the bucket to the normal ground level loading positionhaving the desired tilt attitude, with such result being rapidly andconsistently achieved without the requirement for a high degree ofoperator skill and without loss of time.

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BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a schematic perspective viewof a front end loader employing one embodiment of the invention.

FIGS. 25 are schematic fragmentary side elevational views, partially insection, illustrating an operative embodiment of the invention;

FIG. 2 showing the linkage arrangement with the scoop edge of the bucketin the horizontal position at the surface;

FIG. 3 showing the linkage arrangement of the bucket in full tilt backposition at the surface;

FIG. 4 showing the linkage arrangement with the bucket in the carryposition at the top before dumping; and

FIG. 5 showing the linkage arrangement with the bucket in the full dumpposition at the top.

DESCRIPTION OF THE PREFERRED EMBODIMENTS It is a particular feature ofthis invention to employ a linkage arrangement connecting a bucket to afront end loader type vehicle such that: (l) the bucket can be in thefull dump position at the top in dumping its load and be properlypositioned 'with its scoop side substantially parallel with the surfacefrom which the material is to be scooped by simply lowering the mainbeam and (2) the bucket can be elevated from tilt back position at thesurface to top position without spilling the load by simply elevatingthe main beam. Expressed otherwise, no adjustment of the tilting meansis required to lower the bucket from its top dump position to effectproper positioning of the bucket for scooping another load, or toelevate a loaded, tilted back bucket from the surface to its top carryposition without spilling the load. Thus, a faster loading operation maybe effected. Moreover, less skilled operators are required, effectingfurther savings and lessening dilficulties in obtaining competentpersonnel.

The invention can be clearly understood by referring to the figures. InFIG. 1, front end loader type vehicle 11 has its frame 13 mounted onwheels 15 and a prime mover 17 is mounted on the opposite end of vehicle11 from bucket 19. Prime mover 17 may be an internal combustion engine.It develops the power required for locomotion as well as to operate thevarious accessories, such as hydraulic pumps (not shown). A main beam 21is pivotally attached at its inner end to a first point 23 on frame 13for pivotal movement about a first transverse horizontal axis disposedat a first location. Bucket 19 is pivotally attached to outer endportion 25, or other end, of main beam 21 and is adapted to scoop a loadfrom a surface, to retain the load during elevation to a top position,and to dump the load above and in front of vehicle 11. As can be seenfrom FIG. 2 bucket 19 is pivotally attached to the outer end portion 25at some distance above smooth surface 27 when the scoop side 29 withcutting edge 31 is parallel with the surface, ordinarily substantiallyhorizontal. In this Way vehicle 11 can be moved forward to scoopmaterial from surface 27 and fully load bucket 19 without imposingsignificant forces tending to tilt bucket 19 backwardly. By properlyconnecting outer end portion 25 to bucket 19, scoop side 29 and cuttingedge 31 operate substantially as an extension of main beam 21.

Elevating means; such as, hydraulic cylinder 33; is connected to mainbeam 21 and to frame 13 for elevating main beam 21, consequently liftingthe bucket and its contents.

Bucket tilting means, referred to as tilting means; such as, secondhydraulic cylinder 35; for tilting bucket 19 about outer end portion 25of main beam 21, is attached to frame 13 at a second point 37 forpivotal movement about a second transverse horizontal axis disposed at asecond location. Tilting means 35 includes a lineal extensible member;such as, piston shaft 39.

Also, as part of the linkage arrangement to effect tilting of bucket 19;linking means, such as lever 41, is pivotally attached to bucket 19 andis ultimately connected via a bell crank 43 with tilting means 35 and isoperable to tilt bucket 19 in either direction about the outer endportion 25 of main beam 21 in response to force from the tilting means.

To complete the linkage arrangement and allow the invention to beeffective, a bell crank 43 is interposed between and connected to lever41 and to piston shaft 39. Bell crank 43 is thus connected at thirdpoint 45 with lever 41, for pivotal movement about a third traversehorizontal axis; and at fourth point 47 with piston shaft 39 for pivotalmovement about a fourth transverse horizontal axis. Bell crank 43 ispivotally attached also to main beam 21 at an intermediate point 49 forpivotal movement about a fifth transverse horizontal axis. Bell crank 43is thereby effectively divided into two lever arms, A and B. First leverarm A is formed between intermediate point 49 and fourth point 47connected with piston shaft 39. Second lever arm B is formed betweenintermediate point 49 and third point 45 connected with lever 41. Theratio of the length of the second lever arm to the length of the firstlever arm; i.e., B/A; must be at least 1.4. The length of second leverarm B is fairly well constrained since it must be pivotally attached tothe main beam and yet not extend so low as to encounter surface 27. Itis readily apparent that from the point of view of economic feasibility,lever arm A cannot be shortened so short that tilting means must beuneconomically powerful to effect the tilting of bucket 19. There is apractical maximum of about 2 for the ratio of the length of the secondlever arm to the length of the first lever arm.

Employing this basic limitation on the bell crank and employingconventional empirical design techniques, the respective points and axescan be located, and the main beam, the linking means, the tilting meansand the bell crank can be proportioned and pivotally connected to effectthe following results:

(1) The scoop side of the bucket will be capable of forming angles, withrespect to a reference plane that is horizontal when the vehicle ishorizontal, within the following ranges: 45-49 degrees tip-back at thesurface position; 51-60 degrees carry at the top position; 45-57 degreesbelow the reference plane maximum dump at the top position; and morethan 45 degrees below the reference plane maximum dump at the surfaceposition;

(2) The bucket can be moved from the maximum dump position at the top tothe normal loading, or horizontal position at the surface position byonly lowering the main beam and maintaining the lineal extensible memberextended substantially the same distance from the second axis; and

(3) The loaded, tilted back bucket can be raised to the top withoutspilling the load by only raising the main beam.

The empirical design techniques are well known to those skilled in theart and need not be discussed in detail herein. They representcompromises between conflicting needs, and reflect the impracticality oftheroetical design, because of the numerous possible combinations ofvariables.

While the design of the main beam, the linking means, the tilting meansand the bell crank to effect the results enumerated hereinbefore can beperformed empirically, the following guide lines facilitate placement ofpoints and axes, proportioning of lengths, and location of pivotalconnections to achieve the final result desired. Once the length of mainbeam '21 has been chosen to place bucket 19 ahead of front wheel 15 andlong enough to allow as higha positioning at the top carry position asdesired, the location of first point 23 and, hence, the location of thefirst "transverse horizontal axis must be chosen. While it is desirablethat first transverse horizontal axis be as near the center of gravityof the vehicle as possible from a point of view of aligning the forces,it is also desirable to be able to effect the top carry position withouthaving an unduly long main beam. The main beam may be shaped to avoidprotuberances of the vehicle; such as, the axle between the frontwheels; without unnecessarily increasing its length. The remainingelements and the location of points and axes can be expressed asproportions of the length of the main beam. For example, a length X maybe chosen as the straight line length between the ends of the main beam.On this basis the first transverse horizontal axis, or first point 23,is located on the vehicle at a height of about 0.6X above the smoothsurface when the vehicle is substantially horizontally supported by thesurface. It has been observed on the designs which have worked thatfirst point 23, second point 37, and fourth point 47 form asubstantially straight line when bucket 19 is in position to scrape aload with its scoop side 29 substantially horizontal and contiguous withthe surface 27 when surface is horizontal. Moreover, the are describedby the tfifth transverse horizontal axis through intermediate point 49on main beam 21 and the bell crank 43 substantially coincides with thearc described by the fourth transverse horizontal axis after maximumtilt back of the bucket during about the first /3 of the elevating ofthe bucket to the top carry position but falls outside during the last/3 in order to retain bucket in the carry position during elevating. Abell crank length of about 05X and divided into a first lever arm ofabout 02X and a second lever arm of about 03X to give a ratio of thesecond lever arm to the first lever arm of about 1.5 may be employed.The outer end portion of the main beam is connected to the bucket at apoint about 0.09X above the surface when the scoop side of the bucket iscontiguous with the horizontal surface. The fifth transverse horizontalaxis passing through intermediate point 49 is located about 0.6X fromthe first transverse horizontal axis and about 0.1X from and normal to astraight line connecting the first transverse horizontal axis and theouter end portion of the main beam. The tilting means in the fullyextended position effecting full tilt back of the bucket at the surfaceis about 05X and in the full dump position at the top is about 0.4X. Thelinking means is about 0.2X measured from the third point to its pivotalconnection with the bucket. The bucket is connected to the linking meansand the other end of the main beam at a distance along its bottom memberseparated by about 0.1X. The bucket in the full tilt back position atthe surface clears the front wheels by about 0.1X. The elevating meansis connected to the frame about 0.5X back of the center of the frontwheels and to the main beam about 0.4X from the first point and raisesthe main beam through at least from the surface position to obtain thenecessary height of dump without having an unduly long main beam.

As can be seen in FIG. 1, the preferred embodiment employs pairs ofelements described hereinbefore. That is, a pair ofmain beams 21 areemployed, as are pairs of cylinders for each of elevating means and oftilting means, and bell cranks.

The linkage arrangement and operation is best illustrated in FIGS. 2-5.The operation in which scoop side 29 of bucket 19 is scooped alongsurface 27 by forward motion of vehicle 11, as illustrated in FIG. 2,has been described hereinbefore and will not be repeated.

Once bucket 19 is loaded with the material scooped from surface 27, itis tilted back as illustrated in FIG. 3. Tilt back is effected byextension of piston shaft 39, rotating bell crank 43, pulling lever 41to tilt back bucket 19. The angle 51 of tilt back is within the range45-49 The loaded bucket may be carried in this position but has theobvious disadvantage of encountering low obstructions in advance of thefront wheels 15. Therefore, it is,

ordinarily, advantageous to elevate the loaded bucket to the top beforeit is carried since this also improves visibility of the areaimmediately in front of the wheels and since the loaded bucket must belifted before it can be dumped into a carrying vehicle.

An advantage of this invention is that the loaded, tilted back bucket;i.e., the loaded bucket in the tilted back position; can be elevatedfrom the surface position to the top carry position without adjustmentof piston shaft 39. All that is required is operation of hydrauliccylinder 33 to elevate main beam 21 as shown in FIG. 4. Piston shaft 39is retained with the same length of protrusion; yet, by linkagearrangement, through bell crank 43 and lever 41, loaded bucket 19 isretained in the carry position with the proper tip back to preventspilling of the load either from cutting edge 31 in one direction or top53 in the other direction. In fact, at the top carry position, scoopside 29 of bucket 19 forms an angle 55 of carry at the top positionwithin the optimum range of 51-60 with respect to a reference planeparallel with surface 27. In the top carry position illustrated in FIG.4 the front end loader may be positioned near a dump receptacle toreceive the load since the operator has good visibility and can steervehicle 17 at its mid-point by steering means 56 (FIG. 1). Suchmid-point steering is not critical to the operation of the inventionsince any other method of steering the front end loader type vehicle canbe employed. The mid-point steering is well known and need not bedescribed herein.

Once positioned over the dump receptable to receive the load, the pistonshaft 39 is retracted part way to effect a full dump position,illustrated in FIG. 5. A mechanical stop 57 is employed in conjunctionwith bucket 19 and main beam 21 to facilitate effecting a full dumpposition without careful positioning of piston shaft 39 by the operator.The operator can simply pull the lever to the retract position andpartially retract piston shaft 39. When bucket 19 hits the mechanicalstop, a relief valve is opened to bypass hydraulic fluid aroundhydraulic cylinder 35; whereupon the operator releases the retract leverwhich closes off valves to the hydraulic cylinder and holds thisposition of piston shaft 39 by liquid lock. As can be seen from FIG. 5,bell crank 43 does not quite align with lever 41 such that there is amoment arm to rotate bucket 19. Dump angle 59, which the scoop side ofbucket 19 makes with the surface 27, is within an optimum range of45-57, measured below a reference plane parallel with the surface. Aminus sign is sometimes employed simply to designate that the angle ismeasured opposite from the others, or below the reference plane.

As indicated hereinbefore, a primary advantage of this invention is thatelevating means 33 can be retracted to lower main beam 21 and angle 59returns to as the bucket reaches the surface. Thus, the loader is readyto scoop an additional load from surface 27 without requiring anyadjustment of tilting means 35 by the operator. Specifically, theoperator can change the position illustrated in FIG. to that illustratedin FIG. 2 simply by moving the lever effecting retraction of piston inhydraulic cylinder 33-.

The cycle; of scooping a load, tilting the bucket into the carryposition, lifting the bucket to the top carry position and positioningit over and dumping into a dump receptacle and returning to scoopanother load; is re peated as necessary.

One vehicle having the approximate proportions and location of pointsand axes listed in the table has been found to be particularlyattractive in effecting the results of the invention. The listedempirical design criteria are within the general set outlinedhereinbefore and those design criteria that have been employed withoutchange in effecting the results of the invention are not again listed inthe table.

6 TABLE Element or location: Proportion Main beam 21 X Bell crank 430.514X

First lever arm A 0.20X Second lever arm B 0.322X' B/A 1.56 Distance offirst point 23 above horizontal surface 0.65X

Distance from horizontal surface to other end 25 of main beam mounted tobucket with scoop side on the surface 0.094X Intermediate point 49:

Distance from first point 23 0.618X Distance normal to straight lineconnecting first point and other end of main beam 0.128X Tilting means:

Fully extended 0.526X In the full dump position at the top 0 .444X Fullyretracted effecting full dump at the surface 0.378X Linking means,between pivotal connections 0.234X Bucket:

Distance between pivotal connections 0.144X Distance bucket clears frontwheel in full tilt back position at the surface 0.1OX

Elevating means connection:

Distance from connection on frame to the center of the front wheels0.4-75X Distance from connection on main beam to the first transversehorizontal axis 0.35X Angle through which main beam is raised fromsurface to top 8t1-83 Although the invention has been described with ahigh degree of particularity, it is understood that the presentdisclosure has been made only by Way of example and that numerouschanges in the details of construction and the combination andarrangement of parts may be resorted to without departing from thespirit and the scope of the invention.

What is claimed is:

1. In a front end loader type vehicle having a frame mounted on wheelsand having a prime mover, the improvement comprising:

(a) a main beam attached at an inner end portion to a first point onsaid frame for pivotal movement about a first transverse horizontal axisdisposed thereat;

(b) a bucket pivotally attached to said main beam at an outer endportion thereof and adapted to scoop a load from a surface, to retainsaid load during lifting, and to dump said load above and in front ofsaid vehicle;

(c) elevating means connected to said main beam and to said frame forelevating said outer end portion of said main beam;

((1) bucket tilting means attached to said frame at a second point forpivotal movement about a second transverse horizontal axis disposedthereat and including a lineal extensible member; and

(e) linking means pivotally attached to said bucket, and a bell crankpivotally connected to said linking means and to said tilting means,operable to tilt said bucket in either direction about said other end ofsaid main beam in response to force from said tilting means; said bellcrank being connected to said linking means at a third point for pivotalmovement about a third transverse horizontal axis and to said tiltingmeans at a fourth point for pivotal movement about a fourth transversehorizontal axis and pivotally attached to said main beam at anintermediate point for pivotal movement about a fifth transversehorizontal axis, forming a first lever arm between said intermediatepoint and said fourth point and a second lever arm between saidintermediate point and said third point, such that the ratio of thelength of said second lever arm to the length of said first lever arm isat least 1.4 and no greater than 2; said first and second transversehorizontal axes being located such that, and said main beam, saidlinking means, said bucket tilting means, and said bell crank beingproportioned and pivotally connected such that the scoop side of saidbucket will be capable of forming angles, with respect to a referenceplane parallel to a horizontal surface supporting said vehicle, withinthe following ranges: 45-49 tip back at the surface position; l60 carryat the top position, 4557 below the reference plane maximum dump at thetop position, and more than 45 below the reference plane maximum dump atthe surface position, and such that said bucket can be moved from themaximum dump position at the top to a normal loading position whereinthe scoop side of said bucket is in a horizontal scoop position at saidhorizontal surface by only lowering said outer end portion of said mainbeam and maintaining said lineal extensible member extendedsubstantially the same distance from said second point, and such thatthe loaded, tilted back bucket can be elevated to the top Withoutspilling the load by only elevating said outer end portion of said mainbeam.

2. The vehicle of claim 1 wherein said first point, said second point,and said fourth point form. a substantially straight line when saidbucket is in said normal loading position.

3. The vehicle of claim 1 wherein said first point, said second point,and said fourth point form a substantially straight line when saidbucket -is in said normal loading position, wherein the are described bysaid fifth transverse horizontal axis through said intermediate point onsaid main beam and said bell crank substantially coincides with the aredescribed by said fourth transverse horizontal axis through said fourthpoint after maximum tilt back of said bucket during about the first /3of said elevating to said top position and falls outside thereof duringthe last /3, and wherein said elements are proportioned as follows: saidmain beam is X in length; said bell crank is about 05X, has a firstlever arm of about 02X and a second lever arm of about 0.3X to give aratio of said second lever arm to said first lever arm of about 15; saidfirst transverse horizontal axis through said first point is locatedabout 06X above said surface; said outer end portion of said main beamis connected to said bucket at a point about 0.09X above said surfacewhen said scoop side of said bucket is substantially contiguous withsaid surface; said intermediate point is located on said main beam about0.6X from said first point and at a distance, normal to a straight lineconnecting said first point and said outer end portion of said mainbeam, of about 0.1X; said tilting means in the fully extended positioneffecting full tilt back of said bucket at said surface is about 0.5Xand in the full dump position at the top is about 0.4x; said linkingmeans is about (12X measured from said third point to its pivotalconnection to said bucket; said bucket is connected to said linkingmeans and to said outer end portion of said main beam at pivotalconnections separated by about 0.1X', said bucket in the full tilt backposition at said surface clears said front wheel by about 0.1X; and saidelevating means is connected to said frame about 05X back of the centerline axis of the front wheels and to said main beam about 0.4X from saidfirst point and raises said main beam through at least from said surfaceposition to its top position.

4. The vehicle of claim 3 wherein said elements are proportioned asfollows: said main beam is X in length, said bell crank is about 0.514X,has a first lever arm of about 0.20X, and a second lever arm of about0,322X, forming a ratio of said second lever arm to said first lever armof about 1.56; said first transverse horizontal axis through said firstpoint is about 0.65X above said surface; said outer end portion of saidmain beam is connected to said bucket at a point about 0.094X above saidsurface when said scoop side of said bucket is substantially contiguouswith said surface; said intermediate point is located on said main beamabout 0.618X from said first point and at a distance, normal to thestraight line connecting said first point and said outer end portion ofsaid main beam, of about 0.128X; said tilting means in said fullyextended position is about 0.526X, in said full dump position at the topis about 0.444X, and in a fully retracted position eifecting full dumpat the surface is about 0.378X; said linking means is about 0.234Xmeasured from said third point to its pivotal connection to said bucket;said bucket is connected to said linking means and to said outer endportion of said main beam at pivotal connections separated by about0.144X; said bucket clears said front wheel in full tilt back positionat said surface by about 0.10X; said elevating means is connected tosaid frame about 0.475X back of the center line axis of said frontwheels and to said main beam about 0.35X from said first point andraises said main beam through 8183 from said surface position to its topposition.

References Cited UNITED STATES PATENTS 2,936,086 5/1960 Pueschner et al.2l4776X 3,105,603 10/1963 Beyerstedt et al. 214-776X 3,227,300 11/ 1966Kampert 214-776X 3,250,411 5/1966 Salna et al. 214-776 3 ,272,264 9/1966 Antolini 214776X 3,411,647 11/ 1968 Zimmerman 2l4-776X ALBERT J.MAKAY, Primary Examiner

